transom mount, in hull, thru-hull...?

JohnVTX · Jul 10, 2017

This is what I did with my 30 using the transducer that was designed for transom mount....You do not need to spend another $100. Use the one that comes with the unit and glue to hull with clear silicone. No need to use epoxy. Completely encase it. The key is no air bubbles. Ideal location is in front of keel, but I have mine about 2 feet behind keel. It works perfectly. Every once in awhile, because I am behind keel, I will get some turbulence that loses signal for up to 15 seconds or so.

Justin_NSA · Jul 10, 2017

I mounted mine on my Mac26S to the transom. Never had good luck with wax or epoxy on the hull. Just my experience. Mine was mounted so it was only in the water when I had weight in the cockpit. It had a water temp sensor that only worked submerged too.

JohnVTX · Jul 10, 2017

Justin_NSA said:
I mounted mine on my Mac26S to the transom. Never had good luck with wax or epoxy on the hull. Just my experience. Mine was mounted so it was only in the water when I had weight in the cockpit. It had a water temp sensor that only worked submerged too.

Isn't yours a water ballast boat? If so you cannot shoot thru the hull.

Justin_NSA · Jul 10, 2017

JohnVTX said:
Isn't yours a water ballast boat? If so you cannot shoot thru the hull.

It doesn't span the full length. Owners typically stick them in the lazerette or far up in the bow.

JohnVTX · Jul 10, 2017

Justin_NSA said:
It doesn't span the full length. Owners typically stick them in the lazerette or far up in the bow.

Cannot shoot through foam or any double hull.

Justin_NSA · Jul 10, 2017

JohnVTX said:
Cannot shoot through foam or any double hull.

Right. Just single thickness 'glass in both areas. It has worked for others. I just never had luck with it so I mounted in back . Only failed when I heeled over on a starboard tack and it was out of the water.

thinwater · Jul 10, 2017

Through hull, just in front of the keel. There is no good reason for a comrpomise installation.

I've had transom and in-hull, and they just don't work as well. If is is bumpy or you are moving fast, they fail. Just do it right.

Fitting a through hull is not that big of a deal. Grind the inside smooth, epoxy on a backing plate, drill through both, and seal according to the instructions. If it is a cored hull, seal the core well by removing some core and replacing it with either solid glass or thickened epoxy.

Jacktar · Jul 10, 2017

In hull, just between the forward and aft storage compartments in the v berth, take a small ball of toilet wax and squish the transducer into in and squash onto the hull inside. Firmly squash both and in and out in 5 minutes, only time consuming is laying the connector cable around to depth finder. Best route is starboard side down the settee compartment bottom.

Crazy Dave Condon · Jul 11, 2017

As stated the keys for adding to the inside hull is no foam or wood in the hull, sand off gel coat and clean with alcohol or acetone, add your filler to put a transducer in insuring no air bubbles. Believe it or not, plumbers putty works and takes several hours to dry. Did not think it worked but several years ago I did one that way and still works today for a friend Kermit.

Gene Neill · Jul 11, 2017

My boat came with a transom-mount transducer, mounted in toilet wax. You could tell it had been there for quite some time, and was working fine. But after a year or so in the Florida sun (the boat came from north Georgia), I guess it got really hot and the wax softened up and the transducer kinda fell over. No biggie, I cleaned up all the wax and re-mounted it the same way, using plumber's putty instead of wax. Works great, with no slowly-spreading ugly waxy residue.

Justin_NSA · Jul 14, 2017

+1 on plumbers putty vs wax in hot climates. When I put in my heated tile floor in our bathroom, the instructions with the heating element said to give the toilet some clearance because it can melt the wax!

Gene Neill · Jul 16, 2017

Are you absolutely sure? That bulkhead is almost entirely hollow on my boat.

rpludwig said:
assuming the unit is mounted outside on cockpit bulkhead, port or stbd where I usually see 'em, how did you guys deal with (concealing) the wiring inside the cabin? Bulkhead is solid there except the extreme outboard edge, 3-4", thoughts? Really have trouble dealing with exposed wires/cables.....other than building a chart rack over them (2 cables - one for pwr, one for transducer are exposed), or hanging dirty laundry there I'm stumped...

BlowMeAway · Jul 16, 2017

Thanks @rpludwig for starting this subject up again. I too purchased a Lowrance Hook7 on sale a few months ago from Gander Mountain during a close-out. The instructions clearly state that the transom mount transducer can be mounted as a shoot-through hull sounder. I've selected a spot under the starboard settee for mounting against the hull on my H30. Unfortunately the transducer cable is a bit short to place where I really wanted it in front of the keel. My chosen spot puts the transducer behind the keel and off to the starboard side a bit. The dead rise angle is a bit more than 10 degrees, but I think it will suffice, I don't see anyway for the transducer to be mounted parallel to waterline.

I like the plumbers putty idea. I think I'll try that instead of using the recommended epoxy. If it works for Crazy Dave and Kermit that's good enough for me.

This is what came with the Hook 7 package, and I've fashioned a swing arm to attach the unit inside the companionway. That swing arm concept was presented in another thread a few months ago and I really liked that idea. Thanks all for any additional thoughts or concerns that I may have overlooked.

Gene Neill · Jul 17, 2017

rpludwig said:
Gene...yea, it's solid there, mine's an 84, your's an 86+ IIRC, perhaps the difference....I'm puzzled... (and not fond of the swing arm approach) will try & post a pic of that area tmrro.

((hey btw, you ever get that Corian job done for the Admiral???))

Haven't even started it yet. We both want to visit a showroom somewhere and see the available colors/patterns in person. Haven't found anywhere nearby yet, and there are a million other things going on ... you know how it is.

Milton.Audas · Jul 17, 2017

I have the Hook 5 with the standard transducer that comes with it. I mounted the transducer under the forward V-berth using a silicone gel and then worked the transducer onto it to void out any bubbles. Works great !! Depth is accurate (checked with a lead-line) and scans look great also. Wonderful clarity. The chart plotter is cool, allowing me to mark spots in the channel with low water. The cost on these is great for all of the benefits and features.